Posttraumatic Stress Disorder (PTSD) is a highly prevalent, chronic psychiatric disorder that imposes a major health burden, is associated with marked occupational and social dysfunction, and occurs with significant high degrees of psychiatric and medical comorbidity. Despite its prevalence and devastating impact, available treatments for PTSD have been found to be less effective for Veterans with PTSD. Evidence based pharmacotherapy and psychotherapy approaches have had modest success in improving symptoms and function in this population due to limitations both in terms of tolerability and maximal efficacy. Therefore, innovative interventions for the treatment of PTSD are sorely needed for Veterans with PTSD. The application of non-invasive neuromodulation technologies is developing rapidly across neuropsychiatry. The availability of new devices, coupled with increased knowledge of underlying neurocircuitry relevant to psychiatric illness, sets the stage for economically advantageous and innovative clinical applications of technologies for PTSD treatment. There is an established body of literature that supports the efficacy of non-invasive neuromodulation for treatment of depression, although excitement for this approach for PTSD has been tempered by lengthy administration times and a paucity of data on whether changes in PTSD symptoms occur alongside changes in quality of life or social and occupational function. The aim of the proposed research is to examine the potential of intermittent theta-burst stimulation (iTBS) as an intervention for PTSD in Veterans. TBS holds particular promise for PTSD as can deliver a large number of stimulations rapidly, and its pattered delivery may particularly affect key brain regions involved in PTSD. An important focus of this research is evaluating whether changes in quality of life and function vary with changes in PTSD symptom severity due to TBS. To this end, we propose to conduct a pilot study of 55 Veterans with PTSD randomized to receive either TBS or sham, with three Specific Aims: 1) determine the feasibility of recruitment and randomization, 2) determine the acceptability of TBS, and 3) to provide preliminary evidence of the effects of iTBS on changes in symptoms alongside functional outcomes. This project will lay the groundwork in terms of feasibility, acceptability and methodology for a subsequent randomized controlled trial with adequate statistical power to test both the efficacy of adjunct TBS for PTSD and increasing quality of life for Veterans with PTSD. The longer-term significance of this project lies in the potential for implementing TBS for PTSD and its combination with psychotherapy, to create a powerful, individualized rehabilitation option for Veterans with PTSD.